U.S. Commandos Hunted the Viet Cong With Silent Revolvers

The guns’ ‘special’ rounds were quiet but lacked stopping power

Since World War II, America’s elite forces have used quiet firearms for missions where it pays to be discreet. While sound suppressors—commonly referred to...

Since World War II, America’s elite forces have used quiet firearms for missions where it pays to be discreet. While sound suppressors—commonly referred to as silencers—remain in service today, U.S. commandos once carried revolvers with cartridges specially designed to muffle gunshots.

In the 1960s, the AAI Corporation developed the cartridges for the U.S. Army’s and Navy’s rifles, pistols and shotguns. The ground combat branch’s Special Forces and Rangers tested the unique ammunition in Vietnam.

While they offered many advantages, AAI’s products failed to win any widespread acceptance in the halls of the Pentagon. The rounds were expensive and ineffective at even moderate ranges.

“Throughout the history of firearms, gun noise has been of considerableconcern to the military,” stated a 1968 Army report on silencers. “To the enemy, gun noise reveals presence and, often, the location of the firer, thus inviting defensive or offensive reaction.”

In most modern guns, the sound of the gunshot comes primarily from bottled-up gases escaping as the bullet leaves the barrel—like uncorking a bottle of champagne. A sound suppressor can help muffle the bang by trapping these fumes.

But even with these devices, the gunshot is never entirely undetectable.

In the early 1960s, Army weaponeers looked at alternatives that would completely eliminate the sound of the propellant exploding. So-called “piston cartridges” offered a possible solution.

A normal cartridge contains a casing—which contains gunpowder—and a bullet wedged into an opening at the top. When the propellant detonates, the bullet explosively detaches from the casing, and goes flying through the barrel toward its target.

In a piston cartridge, the case is completely sealed. A plunger transfers the force of the explosion to the slug—like the cue ball striking another in a game of pool.

With the violent reaction contained inside the body of the projectile, the design is effectively silent. A gun shooting these types of rounds produces no muzzle flash or smoke, either.

By 1962, the Army had piston rounds available for .30-caliber rifles and .38-caliber revolvers. The ground combat branch’s fledgling Special Forces soldiers also planned to develop a new weapon to go along with the ammunition.

Left—a diagram showing the function of a piston cartridge. Right—artists conception of a “silent weapon.” Army art via SmallArmsoftheWorld.com

The elite soldiers—and the friendly locals they expected to work with—needed the gun “to escape detection, terrorize the enemy, and efficiently complete missions of sabotage, reconnaissance and assassination,” according to a report from the Army’s Chief of Ordnance.

On top of that, the Army technicians felt the final design could silently take out sensitive vehicles and gear like aircraft, missiles, radar dishes and electronics. The guns would be perfect for taking out enemy patrols and snipers.

For the report, the artists drew up a relatively crude hand cannon that looks equal parts revolver and submachine gun. The concept features a folding butt-stock and simple sights.

Commandos could use the special firearms to “eliminate sentries, guards, guard dogs, military and civilian personnel and collaborators,” the technical document suggests.

In the end, tunnels rather than traitors turned out to be the real impetus behind the new revolver. The Viet Cong dug elaborate subterranean networks to hide guerrilla fighters and supplies from American firepower.

Soldiers who volunteered to scour these amazingly complex tunnels couldn’t carry full-size M-16 rifles with them through the narrow entry points. M-1911 pistols were their only means of defense.

However, the tight passages amplified the sound of gunshots. These U.S. “tunnel rats” could quickly go deaf from firing their pistols at enemy fighters.

To try and save the soldiers’ ears, Army commanders scrounged up silenced .22-caliber handguns. The Limited War Laboratory at Aberdeen Proving Ground in Maryland also sent suppressed .38 caliber revolvers—but without any special piston rounds.

Left—AAI’s Special Purpose Quiet Revolver. Right—a diagram showing the function the special .44-caliber shot shells. Army photos and art

Enter the AAI Corporation. Six years after first exploring piston-cartridges, the Army hired the Baltimore company to build a dedicated “tunnel weapon.”

AAI’s gun was a modified .44-caliber Smith and Wesson revolver. The weapon fired piston cartridges loaded with 15 steel pellets, making it a miniature shotgun. The Army quickly sent 10 of the unique revolvers and almost 1,000 rounds of ammunition to South Vietnam for tests.

While intended for tunnel-scouting soldiers, the 23rd and 25th Infantry Divisions both handed the weapons over to their Ranger units. Special Forces soldiers reportedly got some of the guns, as well.

“The tunnel weapon was found to be ideally suited for ambushes,” the final evaluation report says. As originally expected, the elite troops used their silent guns on various occasions to ambush and kill enemy officers.

Above — an Army Ranger leaves a helicopter for a mission in Vietnam. At top — a “tunnel rat” poses inside a Viet Cong passage. Army photos

At the same time, AAI was offering similar ammunition to the Navy’s SEALs. The sailing branch purchased a stock of silent full-size, 12-gauge shells for their own experiments.

“The only sound heard when firing the silent shotgun shell was the click of the shotgun’s firing pin,” writes noted SEAL historian Kevin Dockery in Special Warfare Special Weapons. “Though the … shell was not completely silent, it made a weapon firing it very hard to hear and effectively unnoticeable.”

But the ammunition had serious restrictions. While silencers can slow bullets to varying degrees, piston cartridges launch their projectiles at even lower velocities.

“There were several instances … in which the tunnel weapon failed to incapacitate an enemy soldier after he was hit,” Army evaluators lamented. In one instance, “the [Viet Cong] officer was shot at a distance of approximately 10 feet,” their report explains.

“The first round struck a large leather pocketbook, filled with papers, that was being carried across the officer’s chest,” the shooter reported. “The second round struck his stomach, knocked him over, but failed to kill him.”

There was another problem—the sealed-up rounds were difficult and expensive to make. This is one reason why the Navy never sent any special shotgun shells to SEAL teams in Southeast Asia.

“The high cost was not considered balanced by the usefulness of the round as other suppressed weapons were becoming available, and the project was shelved,” Dockery says.

The Navy didn’t buy any more rounds from AAI, either. In 1973, the Army followed suit and canned their revolver program. “No further development is planned,” progress reports from Aberdeen declare. “Several weapons and some ammunition will be available … if a special need arises.”

Today, American commandos regularly use suppressed guns, but don’t have a pressing need for the complicated piston cartridges.